The present invention relates to a means of loading and unloading a pump cassette or other fluid delivery device into a medical pump.
Modern medical care often involves the use of medical pump devices to deliver fluids and/or fluid medicine to patients. Medical pumps permit the controlled delivery of fluids to a patient, and such pumps have largely replaced gravity flow systems, primarily due to the pump's much greater accuracy in delivery rates and dosages, and due to the possibility for flexible yet controlled delivery schedules. Of the modern medical pumps, those incorporating a diaphragm cassette are often preferred because they provide more accurately controlled rate and volume than do other types of pumps.
A typical positive displacement pump system includes a pump device driver and a fluid delivery device, including but not limited to a syringe, tubing, section of tubing, or a disposable cassette. The disposable cassette, which is adapted to be used only for a single patient and for one fluid delivery cycle, is typically a small plastic unit having an inlet and an outlet respectively connected through flexible tubing to a fluid supply container and to the patient receiving the fluid. The cassette includes a pumping chamber, with the flow of fluid through the chamber being controlled by a plunger or plunger activated in a controlled manner by the device driver.
One of the requirements for many pumps, including cassette pumps, is that they are able to dictate the stability and proper positioning of the fluid delivery device or cassette when loaded. The stability and proper positioning of the cassette is critical to ensure that any pump elements (including the plunger and/or sensors) that interact with the cassette are precisely aligned and positioned to accurately produce the desired output of the cassette or sense conditions related to the pump.
Previous pumps attempted to accomplish the proper positioning of the cassette by providing a molded seat that a user would manually push the cassette into. Once the cassette is forced into the molded seat, retentive snap elements engage the outer surface of the cassette to hold the cassette within the molded seat.
These previous pumps often have few if any physical elements to ensure proper cassette orientation to the pump. They rely heavily on proper loading by the operator to insure complete seating of the cassette to the pump. Additionally, they may often lack means for monitoring if the cassette was indeed oriented correctly and/or fully seated to the pump.
Other previous pumps have attempted to provide automatic cassette loaders that utilize sensors and alarms when improper cassettes are placed in the loader and to detect when the loader is not fully opened or closed. Specifically, as seen in U.S. Pat. No. 7,258,534 a processing unit is utilized in order to drive a linear actuator to position a carriage to load and unload a cassette. While effective at providing a loader that does not accept inaccurately sized cassettes, ensuring that the cassette loader is fully opened for loading, and providing an alarm if the loader is jammed or not fully closed, problems remain. Such a design is very complex, expensive, has increased maintenance issues, and can be difficult to use.
Therefore, a principal object of this invention is to provide a cost-effective medical pump having a manual loading system that provides clear, stable and proper positioning of the fluid delivery device.
A further object of the invention is to provide a medical pump that monitors proper fluid delivery device loading.
A further object of the invention is to provide a medical pump with a fluid delivery device loading system that is essentially bi-stable and thereby prevents dwelling, parking or inadvertent positioning of the fluid delivery device loading system in any position other than fully open or fully closed.
Another object of the invention is to provide a medical pump having a manual release element for manually ejecting a fluid delivery device from the pump.
Another object of the invention is to provide a medical pump with a cassette loading system having reduced complexity and power requirements.
These and other objects will be apparent to those skilled in the art.